Driving while intoxicated (DWI) remains a substantial and preventable source of morbidity and mortality in the United States. A variety of sanctions and interventions have been attempted to reduce DWI in the U.S., including enhanced DWI enforcement efforts, stricter drunk driving laws, responsible alcohol beverage service training, and alcohol treatment. The Ignition Interlock Device (IID), which requires a driver to blow into a breathalyzer unit installed in an automobile to establish sobriety, reduces drunk driving while installed. The use of IIDs has become widespread: most states in the U.S. now require convicted drunk drivers to install an IID in their cars upon some form of conviction. However, research has conclusively shown that once the IIDs are removed from DWI offenders' cars, DWI recidivism levels return to those comparable to offenders who did not have an IID installed. This indicates that IIDs are effective as long as they are installed, but do not provide any effect beyond the installation period. IIDs do, however, effectively provide a cessation of drunk driving while installed. Proposed here is the systematic development (in Phase I) and randomized efficacy trial of (in Phase II) an intervention designed to extend the drunken driving cessation initially provided by an IID. B-SMART will be a smartphone app that will involve the Concerned Family Member (CFM) of DWI offenders by providing coping skills, communication skills, and strategies to help avoid DWI. Unique to this intervention are the involvement of family members in supporting the DWI offender to not drink and drive, and the use of smartphone technology to make that support immediate, accessible, and diffusible. The content of the intervention will be based on empirically validated couples therapy for those with Alcohol Use Disorders developed by co-Investigator McCrady, translated to a smartphone platform. Phase I of this project will involve the systematic and iterative development of B-SMART, employing: 1) an Expert Advisory Board, 2) a Community Advisory Board, and 3) iterative development, multimedia, and usability focus groups and interviews comprised of CFM and DWI offenders. Specific milestones and deliverables for B-SMART are projected for Phase I. A future Phase II of the project will involve the completion of B-SMART, and a randomized efficacy trial of B-SMART that examines its impact on a variety of alcohol-related dependent variables, including DWI re-arrest. Should B-SMART be demonstrated to impact DWI and DWI re-arrest, government, community, and therapeutic entities, along with families of DWI offenders, will have an important and accessible tool to further reduce the social, health and economic consequences of DWI.